We had a question about removing mildew from a harp so we will cover that plus some general care tips.
First off, to care for your harp always wash your hands before playing the harp to remove any oil and dirt so that it does not get transferred to the harp and strings. Remove jewelry, especially dangling bracelets and necklaces and even long earrings. Do not apply lotions to your hands before playing. Also be mindful that buckles, sequins and buttons on clothing can also scratch your harp. Your harp should be stored in a clean room free from dust and keep the harp away from direct sunlight as well as air currents from heating and air conditioning outlets.
I personally feel that it is not necessary to cover your harp if it is kept in a good environment. This way it is more inviting to sit down and have a play even for a short time. If you do choose to cover your harp and have a cat, be warned that cats like to jump up on harp covers and climb to the top. This endangers your cat and harp should your harp topple over. If your harp is in danger of being bumped my animals or humans, you might consider placing it in a corner to minimize the danger of it be knocked over.
Now to the finish. The first step in keeping your harp looking new is to regularly lightly dust it off and wipe it down with a soft dry cloth and also wipe your strings down after playing especially during warm weather when you may be perspiring. On a regular basis, it is suggested you give your harp a more thorough dusting and wipe down. You may find that a soft paintbrush or stencil brush aids in this to get into the nooks and crannies especially around the discs of a pedal harp and levers on folk harps. If you do find that there is some darkened and built up areas from bodily contact with the wood or even in the extreme some mold or mildew, the steps to follow as needed are: First buff with a soft dry cloth. If this does not do the task, then slightly dampen the cloth followed by a dry cloth. If you still need to get more serious, add a small amount of gentle liquid soap, like hand dishwashing soap to the dampened cloth, followed by a damp cloth to rinse and then finish off with a soft dry cloth.
Avoid wood cleaners and polishers especially if they contain oils such as orange oil or silicon. Oils may damage some finishes and both can cause problems if your harp ever needs to be repaired or repolished. If in doubt, contact the maker of your harp for recommendations depending on the type of finish used.
One product that we have found that can make minor surface scratches disappear is Tibet Almond Stick. This seems to be safe for all the finishes I have used it and is almost like a miracle scratch remover. Just rub the stick which comes in a storage tin over the scratch, buff with a soft cloth and most scratches disappear. You can “Google” it to find sources. Disclaimer, I have no financial interest in this product.